//https://qoj.ac/contest/1404/problem/7685
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define PI acos(-1)
#define LSB(i) ((i) & -(i))
#define ll long long
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define fi first
#define sc second
#define th third
#define fo fourth
#define pii pair<int,int>
#define pll pair<ll,ll>
#define ldb double
#define INF 1e15
#define MOD 1000000007
#define endl "\n"

#define all(data)       data.begin(),data.end()
#define TYPEMAX(type)   std::numeric_limits<type>::max()
#define TYPEMIN(type)   std::numeric_limits<type>::min()
#define MAXN 500007
ll a[MAXN],lst[MAXN];
vector<ll> pos[MAXN];
vector<pll> seg[MAXN],qry[MAXN];
struct Fenwick
{
    vector<ll> BIT; ll n;
    void Init(ll x) {n=x; BIT.assign(n+1,0);}
    void Add(ll x,ll d)
    {
        for(int i=x;i<=n;i+=LSB(i)) BIT[i]+=d;
    }
    ll Psum(ll x)
    {
        ll sum=0;
        for(int i=x;i>0;i-=LSB(i)) sum+=BIT[i];
        return sum;
    }
    ll Sum(ll x,ll y)
    {
        if(x>y) return 0;
        return Psum(y)-Psum(x-1);
    }
};
int main()
{
    ios::sync_with_stdio(false); cin.tie(0);
    ll tt; cin>>tt; Fenwick bit;
    while(tt--)
    {
        ll n,m,rez=-INF; cin>>n>>m;
        for(int i=1;i<=m+1;i++) {pos[i].clear(); seg[i].clear(); qry[i].clear(); lst[i]=0;}
        for(int i=1;i<=n;i++) {cin>>a[i]; pos[a[i]].pb(i);}
        for(int i=1;i<=m;i++)
        {
            if(pos[i].empty()) continue;
            if(pos[i][0]>1) seg[i].pb({1,pos[i][0]-1});
            for(int j=1;j<pos[i].size();j++) seg[i].pb({pos[i][j-1]+1,pos[i][j]-1});
            if(pos[i].back()<n) seg[i].pb({pos[i].back()+1,n});
        }
        for(int i=1;i<=m;i++)
        {
            for(auto [l,r]:seg[i]) qry[r].pb({l,i});
        }
        bit.Init(n);
        for(int r=1;r<=n;r++)
        {
            if(lst[a[r]]) bit.Add(lst[a[r]],-1);
            bit.Add(r,1); lst[a[r]]=r;
            for(auto [l,mex]:qry[r]) rez=max(rez,bit.Sum(l,r)-mex);
        }
        for(int i=1;i<=m+1;i++)
        {
            if(!lst[i]) rez=max(rez,bit.Sum(1,n)-i);
        }
        cout<<rez<<endl;
    }
    return 0;
}